Use os.RemoveAll instead of os.Remove for broken TVN repositories.
Fix mirroring, push to Open Fortress GitLab as well.
Also remove the temporary file if using fallback moving, idiot.
Fallback to copying the file instead of renaming, fixes issues with Plan 9/Windows.
Update Makefile to include COPYING and ATTRIBUTION.
Switch to github.com/minio/sha256-simd for hardware accelerated SHA-256.